U.S. patent application number 13/123403 was filed with the patent office on 2011-08-11 for elevator rope.
This patent application is currently assigned to MITSUBISHI ELECTRIC CORPORATION. Invention is credited to Hiroshi Kigawa, Rikio Kondo, Atsushi Mitsui, Muneaki Mukuda, Michio Murai, Shinya Naito, Hiroyuki Nakagawa, Mamoru Terai.
Application Number | 20110192131 13/123403 |
Document ID | / |
Family ID | 42268732 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110192131 |
Kind Code |
A1 |
Naito; Shinya ; et
al. |
August 11, 2011 |
ELEVATOR ROPE
Abstract
An elevator rope of the present invention includes: a rope main
body; and a covering resin layer that covers the periphery of the
rope main body and comprises a molded product of a composition for
forming the covering resin layer, wherein the composition is
produced by mixing a thermoplastic polyurethane elastomer, a
thermoplastic resin other than the thermoplastic polyurethane
elastomer and an isocyanate compound having two or more isocyanate
groups per molecule. Preferably, a rope main body impregnated with
an impregnating solution comprising a hydroxy compound having two
or more hydroxy groups per molecule and an isocyanate compound
having two or more isocyanate groups per molecule and having a
lower viscosity than a melt viscosity of the composition for
forming the covering resin layer is used as the rope main body. The
elevator rope of the present invention has a stable friction
coefficient that does not depend on temperature or sliding
velocity.
Inventors: |
Naito; Shinya; (Tokyo,
JP) ; Terai; Mamoru; (Tokyo, JP) ; Murai;
Michio; (Tokyo, JP) ; Kigawa; Hiroshi; (Tokyo,
JP) ; Nakagawa; Hiroyuki; (Tokyo, JP) ;
Mukuda; Muneaki; (Tokyo, JP) ; Mitsui; Atsushi;
(Tokyo, JP) ; Kondo; Rikio; (Tokyo, JP) |
Assignee: |
MITSUBISHI ELECTRIC
CORPORATION
Tokyo
JP
|
Family ID: |
42268732 |
Appl. No.: |
13/123403 |
Filed: |
December 9, 2009 |
PCT Filed: |
December 9, 2009 |
PCT NO: |
PCT/JP2009/070597 |
371 Date: |
April 8, 2011 |
Current U.S.
Class: |
57/232 ;
57/241 |
Current CPC
Class: |
D07B 2201/2092 20130101;
D07B 1/162 20130101; D07B 2205/2003 20130101; B66B 7/06 20130101;
D07B 1/22 20130101; D07B 2205/2064 20130101; D07B 2201/2087
20130101; D07B 5/006 20150701; D07B 2205/2064 20130101; D07B
2801/22 20130101; D07B 2501/2007 20130101; D07B 2205/2003 20130101;
D07B 2801/22 20130101 |
Class at
Publication: |
57/232 ;
57/241 |
International
Class: |
D07B 1/06 20060101
D07B001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2008 |
JP |
2008-320679 |
Claims
1-8. (canceled)
9. An elevator rope, comprising: a rope main body; and a covering
resin layer that covers the periphery of the rope main body and
comprises a molded product of a composition for forming a covering
resin layer, wherein the composition is produced by mixing a
thermoplastic polyurethane elastomer and an isocyanate compound
having two or more isocyanate groups per molecule.
10. An elevator rope, comprising: a rope main body; and a covering
resin layer that covers the periphery of the rope main body and
comprises a molded product of a composition for forming a covering
resin layer, wherein the composition is produced by mixing a
thermoplastic polyurethane elastomer, a thermoplastic resin other
than the thermoplastic polyurethane elastomer and an isocyanate
compound having two or more isocyanate groups per molecule.
11. An elevator rope according to claim 10, wherein the rope main
body is impregnated with an impregnating solution comprising a
hydroxyl compound having two or more hydroxyl groups per molecule
and an isocyanate compound having two or more isocyanate groups per
molecule and having a lower viscosity than a melt viscosity of the
composition for forming the covering resin layer.
12. An elevator rope according to claim 10, wherein inorganic
fillers are further mixed in the composition for forming the
covering resin layer.
13. An elevator rope according to claim 12, wherein the inorganic
fillers are in either fibrous or plate-like form.
14. An elevator rope according to claim 10, wherein the composition
for forming the covering resin layer is produced by mixing the
thermoplastic resin and the isocyanate compound in an amount within
the range of 5 to 20 parts by mass in total with respect to 100
parts by mass of the thermoplastic polyurethane elastomer so that
the molded product has a JIS A hardness of 98 or less and a glass
transition temperature of -20.degree. C. or less.
15. An elevator rope, comprising: a rope main body; and a covering
resin layer that covers the periphery of the rope main body and
comprises a molded product of a composition for forming the
covering resin layer, wherein the composition is produced by mixing
a thermoplastic polyurethane elastomer and inorganic fillers.
16. An elevator rope according to claim 15, wherein the rope main
body is impregnated with an impregnating solution comprising a
hydroxyl compound having two or more hydroxyl groups per molecule
and an isocyanate compound having two or more isocyanate groups per
molecule and having a lower viscosity than a melt viscosity of the
composition for forming the covering resin layer.
17. An elevator rope according to claim 15, wherein the composition
for forming the covering resin layer is produced by mixing the
inorganic filler in an amount within the range of 3 to 20 parts by
mass with respect to 100 parts by mass of the thermoplastic
polyurethane elastomer so that the molded product has a JIS A
hardness of 98 or less and a glass transition temperature of
-20.degree. C. or less.
Description
TECHNICAL FIELD
[0001] The present invention relates to an elevator rope for
suspending an elevator car.
BACKGROUND ART
[0002] A sheave having a diameter 40 times or more the diameter of
a rope has been conventionally used in an elevator apparatus in
order to prevent early abrasion or breakage of the rope. Therefore,
in order to reduce the diameter of the sheave, it is also necessary
to make the diameter of the rope smaller. However, if the diameter
of the rope is made smaller without changing the number of ropes,
then there is a risk that a car may more easily vibrate due to load
variations caused by baggage loaded in the car or passengers
getting on and off the car, and rope vibrations at the sheave may
be transmitted to the car. Further, an increase in the number of
ropes results in a complicated structure of the elevator apparatus.
In addition, if the diameter of a driving sheave is made smaller,
driving frictional force is reduced. As a result, the weight of the
car needs to be increased.
[0003] As means for solving such problems, it has been proposed to
use a rope obtained by: twisting a plurality of steel wires
together to form strands; twisting a plurality of the strands
together to forma wire rope; and covering the outermost periphery
of the wire rope with a resin material (for example, see Patent
Literature 1). An elevator using such rope is driven by a
frictional force between a sheave and the resin material forming
the outermost periphery. Therefore, it is desired to stabilize or
improve the friction characteristics of the resin material.
Accordingly, in order to improve the friction characteristics of an
elevator rope, it has been proposed to use a rope covered with a
polyurethane covering material containing no wax (for example, see
Patent Literature 2).
[0004] In general, the friction coefficient of a resin material is
known to heavily depend on sliding velocity and temperature.
Further, viscoelastic characteristics such as dynamic
viscoelasticity of the resin material are known to have velocity
and temperature dependencies which can be converted into each other
(Williams-Landel-Ferry equation (WLF equation)). In addition, such
conversion is achieved for the sliding velocity and temperature as
well in the case of rubber friction, and hence it has been shown
that the viscoelastic characteristics of rubber are involved in the
friction characteristics of the rubber (for example, see Non Patent
Literature 1). [0005] [Patent Literature 1] Japanese Patent
Laid-Open No. 2001-262482 [0006] [Patent Literature 2] Japanese
Patent Laid-Open No. 2004-538382 [0007] [Non Patent Literature 1]
Grosch, K. A.: Proc. Roy. Soc., A274, 21 (1963)
SUMMARY OF INVENTION
Technical Problem
[0008] As is clear from the above-mentioned facts, even in the
polyurethane covering material containing no wax described in
Patent Literature 2, the friction coefficient of the material
itself varies depending on the sliding velocity and temperature,
and hence there has been a problem in that it is impossible to
stably control an elevator. Further, as described in Non Patent
Literature 1, the friction coefficient of rubber has a maximal
value for the sliding velocity. In order to stop an elevator for a
long period of time, it is necessary to maintain the static
condition of a car by the frictional force between a rope and a
sheave. However, such conventional covering material having a large
variation in friction coefficient has a problem in that the
friction coefficient cannot be secured at a certain level or more
at a small sliding velocity, resulting in a misalignment of the
stop position of the car with time. Meanwhile, in order to perform
an emergency stop or sudden stop of the elevator in operation, it
is necessary to brake the elevator by the frictional force between
the rope and the sheave, but the conventional covering material may
cause a decrease in strength or melting by frictional heat. In such
case, there has been a problem in that the friction coefficient
between the rope and the sheave significantly decreases.
[0009] Therefore, the present invention has been made to solve the
above-mentioned problems, and an object of the present invention is
to obtain an elevator rope which has a stable friction coefficient
that does not depend on temperature or sliding velocity.
Solution to Problem
[0010] The inventors of the present invention have made studies on
frictional characteristics of a variety of resin materials. FIG. 1
is an example of results illustrating frequency dependency of loss
moduli in materials having different sliding velocity dependency of
friction coefficients. As is clear from FIG. 1, the inventors have
found that a material having small sliding velocity dependency of
the friction coefficient has small frequency dependency of the loss
modulus in a viscoelastic master curve. Based on such findings, the
inventors have studied the compositions of resin materials, and as
a result, have found that, in order to reduce both the frequency
dependency of the loss modulus and sliding velocity dependency of
the friction coefficient, it is useful to use, as a layer for
covering the periphery of a rope main body, a resin material
obtained by adding a thermoplastic resin other than a thermoplastic
polyurethane elastomer and an isocyanate compound having two or
more isocyanate groups per molecule to a thermoplastic polyurethane
elastomer or a resin material obtained by adding inorganic fillers
to the thermoplastic polyurethane elastomer, thus completing the
present invention.
[0011] That is, the present invention is an elevator rope,
including: a rope main body; and a covering resin layer that covers
the periphery of the rope main body and comprises a molded product
of a composition for forming the covering resin layer, wherein the
composition is produced by mixing a thermoplastic polyurethane
elastomer, a thermoplastic resin other than the thermoplastic
polyurethane elastomer and an isocyanate compound having two or
more isocyanate groups per molecule.
[0012] Further, the present invention is an elevator rope,
including: a rope main body; and a covering resin layer that covers
the periphery of the rope main body and comprises a molded product
of a composition for forming the covering resin layer, wherein the
composition is produced by mixing a thermoplastic polyurethane
elastomer and inorganic fillers.
Advantageous Effects of the Invention
[0013] According to the present invention, it is possible to obtain
an elevator rope which has a stable friction coefficient that does
not depend on temperature or the sliding velocity by using, as a
layer for covering the periphery of a rope main body, a molded
product of the composition for forming a covering resin layer
produced by adding the thermoplastic resin other than the
thermoplastic polyurethane elastomer and the isocyanate compound
having two or more isocyanate groups per molecule to the
thermoplastic polyurethane elastomer or the composition for forming
a covering resin layer produced by adding the inorganic fillers to
the thermoplastic polyurethane elastomer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an example of results illustrating frequency
dependency of loss moduli in materials having different sliding
velocity dependency of friction coefficients (viscoelastic master
curves).
[0015] FIG. 2 is a schematic cross-sectional view of an example of
an elevator rope using strands not impregnated with impregnating
solution.
[0016] FIG. 3 is a schematic cross-sectional view of an example of
an elevator rope according to Embodiment 3.
[0017] FIG. 4 is a schematic cross-sectional view of the vicinity
of an outer layer of an elevator rope.
[0018] FIG. 5 is a conceptual diagram of an apparatus for measuring
the friction coefficient in a small sliding velocity range used in
the Examples.
[0019] FIG. 6 is a conceptual diagram of an apparatus for measuring
the friction coefficient at the time of an emergency stop used in
the Examples.
DESCRIPTION OF EMBODIMENTS
[0020] Embodiments of the present invention are described
below.
Embodiment 1
[0021] An elevator rope according to Embodiment 1 of the present
invention is characterized in that the periphery of a rope main
body is covered with a molded product of a composition for forming
a covering resin layer, wherein the composition is produced by
mixing a thermoplastic polyurethane elastomer, a thermoplastic
resin other than the thermoplastic polyurethane elastomer and an
isocyanate compound having two or more isocyanate groups per
molecule.
[0022] Examples of the thermoplastic polyurethane elastomer used in
this embodiment include an ester-based thermoplastic polyurethane
elastomer, an ether-based thermoplastic polyurethane elastomer, an
ester-ether-based thermoplastic polyurethane elastomer, and a
carbonate-based thermoplastic polyurethane elastomer. The
elastomers may be used alone or in combinations of two or more
kinds thereof.
[0023] Of those thermoplastic polyurethane elastomers, an
ether-based thermoplastic polyurethane elastomer is preferably used
to prevent hydrolysis which occurs in a usage environment. In
consideration of flexibility and durability of the elevator rope, a
polyether-based thermoplastic polyurethane elastomer having a JIS A
hardness (hardness specified by JIS K7215 using a type A durometer)
of 85 or more and 95 or less is more preferably used.
[0024] Meanwhile, from the viewpoint of workability such as the
mixing of the thermoplastic resin other than the thermoplastic
polyurethane elastomer with the isocyanate compound having two or
more isocyanate groups per molecule, a thermoplastic polyurethane
elastomer processed into pellets is preferably used.
[0025] Examples of the isocyanate compound having two or more
isocyanate groups per molecule, which is used in this embodiment,
include: aliphatic isocyanates such as 1,6-hexamethylene
diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, lysine
methyl ester diisocyanate, methylene diisocyanate, isopropylene
diisocyanate, lysine diisocyanate, 1,5-octylene diisocyanate, and a
dimer acid diisocyanate; alicyclic isocyanates such as
4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate,
hydrogenated tolylene diisocyanate, methyl cyclohexane
diisocyanate, and isopropylidene dicyclohexyl-4,4'-diisocyanate;
and aromatic isocyanates such as 2,4- or 2,6-tolylene diisocyanate,
4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate,
xylylene diisocyanate, triphenylmethane triisocyanate,
tris(4-phenyl isocyanate) thiophosphate, tolidine diisocyanate,
p-phenylene diisocyanate, diphenyl ether diisocyanate, and
diphenylsulfone diisocyanate. Those compounds may be used alone or
in combinations of two or more kinds thereof. Alternatively, an
isocyanate prepolymer having isocyanate groups at its molecular
ends, which can be obtained by reacting an active hydrogen compound
such as a polyol or a polyamine with the above-mentioned
isocyanate, can also be used as the isocyanate compound having two
or more isocyanate groups per molecule.
[0026] From the viewpoint of workability such as the mixing with
the thermoplastic polyurethane elastomer, the isocyanate compound
described above is used as a resin composition (hereinafter,
referred to as "isocyanate batch") in the form of powder, flakes,
or pellets, in which the thermoplastic resin other than the
thermoplastic polyurethane elastomer and the isocyanate compound
are preliminarily mixed. Examples of the thermoplastic resin other
than the thermoplastic polyurethane elastomer, which is used in
this case, include an epoxy resin, a polystyrene resin, a polyvinyl
chloride resin, a polyvinyl acetate resin, an ethylene-vinyl
acetate copolymer resin, a polyethylene resin, a polypropylene
resin, and a polyester resin.
[0027] The covering resin layer used in this embodiment is usually
obtained by: mixing the above-mentioned thermoplastic polyurethane
elastomer pellets and the above-mentioned isocyanate batch to
prepare a composition for forming a covering resin layer; and
feeding the composition into a molding machine such as an extrusion
molding machine or an injection molding machine to mold the
composition. The mixing ratio is not particularly limited, but is
preferably adjusted so that the amount of the isocyanate batch is
in the range of 5 parts by mass or more and 20 parts by mass or
less with respect to 100 parts by mass of the thermoplastic
polyurethane elastomer, and the molded product obtained has a JIS A
hardness of 98 or less and a glass transition temperature of
-20.degree. C. or less. If the amount of the isocyanate batch is
less than 5 parts by mass, a covering resin layer having a stable
friction coefficient may not be obtained, while if the amount is
more than 20 parts by mass, the flexibility and durability of the
rope may be impaired. In particular, in the case of using a
thermoplastic polyurethane elastomer having a JIS A hardness of 95,
the isocyanate compound is more preferably blended in an amount in
the range of 5 parts by mass or more and 10 parts by mass or less
with respect to 100 parts by mass of the thermoplastic
polyurethane.
[0028] The reason why the JIS A hardness of the molded product is
specified as 98 or less is that studies by the inventors have
revealed that, in the case where the hardness is more than 98, the
flexibility of the rope is liable to be impaired, resulting in an
increase in the power consumption of the elevator. The JIS A
hardness of the molded product is more preferably 85 or more and 98
or less.
[0029] Meanwhile, the reason why the glass transition temperature
of the molded product (sliding velocity dependency of the friction
coefficient becomes smaller as the glass transition temperature of
the molded product increases, while the elastic modulus of the
molded product becomes larger as the glass transition temperature
of the molded product increases) is specified as -20.degree. C. or
less is that studies by the inventors have revealed that, in the
case where a molded product having a higher glass transition
temperature is employed for an elevator rope as the covering resin
layer, the flexibility of the rope is liable to be impaired or
fatigue failure such as cracking of the covering resin layer is
liable to occur due to stress applied to the covering resin layer
when the rope is bent repeatedly in an environment having a
temperature higher than the glass transition temperature of the
molded product. The glass transition temperature of the molded
product is more preferably -25.degree. C. or less.
[0030] The friction coefficient can be more stabilized against
temperature or sliding velocity by adding inorganic fillers to the
above-mentioned composition for forming a covering resin layer.
Examples of the inorganic filler include: a spherical inorganic
filler such as calcium carbonate, silica, titanium oxide, carbon
black, acetylene black, or barium sulfate; a fibrous inorganic
filler such as a carbon fiber or a glass fiber; and a plate-like
inorganic filler such as mica, talc, or bentonite. The fillers may
be used alone or in combinations of two or more kinds thereof. Of
those, in order to reduce a variation in the friction coefficient,
a fibrous inorganic filler and a plate-like inorganic filler are
preferably used. The composition for forming a covering resin layer
having added thereto the inorganic filler has improved thermal
conductivity compared with a composition for forming a covering
resin layer having added thereto no inorganic filler, and hence the
composition can suppress a temperature variation on a friction
interface, resulting in reduction of the variation in the friction
coefficient even in the case where frictional heat is generated on
the surface of the rope.
[0031] The blending amount of the inorganic fillers may be
appropriately adjusted so that the molded product has a JIS A
hardness of 98 or less and a glass transition temperature of
-20.degree. C. or less.
[0032] It should be noted that the elevator rope according to this
embodiment is characterized by the resin material of the outermost
layer that covers the periphery of the rope main body. Therefore,
the structure of the rope main body is not particularly limited,
but in general, the rope main body contains strands or cords formed
by twisting a plurality of steel wires together as a
load-supporting member. The rope main body in this embodiment may
have a belt shape including the above-mentioned strands or cords.
Meanwhile, in order to improve adhesion between the rope main body
and the covering resin layer, an adhesive for metal and
polyurethane such as Chemlok (registered trademark) 218
(manufactured by LORD Far East, Inc.) is preferably applied in
advance to the above-mentioned strands or cords. Further, the
inorganic filler as exemplified above may be added to the adhesive
for metal and polyurethane.
[0033] According to Embodiment 1, it is possible to obtain an
elevator rope having a small variation in the friction coefficient
in a wide range of sliding velocities from a small sliding velocity
range required for maintaining a static condition of an elevator
car to a large sliding velocity range during emergency or sudden
stops of an elevator in operation.
Embodiment 2
[0034] An elevator rope according to Embodiment 2 of the present
invention is characterized in that the periphery of a rope main
body is covered with a molded product of a composition for forming
a covering resin layer, which is produced by mixing a thermoplastic
polyurethane elastomer and inorganic fillers.
[0035] The thermoplastic polyurethane elastomer and rope main body
used in this embodiment are the same as those in Embodiment 1, and
hence descriptions of them are omitted.
[0036] Examples of the inorganic filler used in this embodiment
include: a spherical inorganic filler such as calcium carbonate,
silica, titanium oxide, carbon black, acetylene black, or barium
sulfate; a fibrous inorganic filler such as a carbon fiber or a
glass fiber; and a plate-like inorganic filler such as mica, talc,
or bentonite. The fillers may be used alone or in combinations of
two or more kinds thereof. Of those, in order to reduce a variation
in the friction coefficient, a fibrous inorganic filler and a
plate-like inorganic filler are preferably used. The composition
for forming a covering resin layer having added thereto the
inorganic filler has improved thermal conductivity compared with a
composition for forming a covering resin layer having added thereto
no inorganic filler, and hence the composition can suppress
temperature variation on the friction interface, resulting in
reduction of variations in the friction coefficient even in cases
where frictional heat is generated on the surface of the rope.
[0037] The mixing ratio between the thermoplastic polyurethane
elastomer and inorganic filler is not particularly limited, but is
preferably adjusted so that the inorganic filler is mixed in an
amount within the range of 3 parts by mass or more and 20 parts by
mass or less with respect to 100 parts by mass of the thermoplastic
polyurethane elastomer and so that the molded product has a JIS A
hardness of 98 or less and a glass transition temperature of
-20.degree. C. or less. If the amount of the inorganic filler is
less than 3 parts by mass, a covering resin layer having a stable
friction coefficient may not be obtained, while if the amount is
more than 20 parts by mass, flexibility of the rope may be impaired
or the covering resin layer may become fragile.
[0038] According to Embodiment 2, it is possible to obtain an
elevator rope having a small variation in the friction coefficient
in a wide range of sliding velocities from a small sliding velocity
range required for maintaining a static condition of an elevator
car to a large sliding velocity range during emergency or sudden
stops of an elevator in operation.
Embodiment 3
[0039] An elevator rope according to Embodiment 3 of the present
invention is characterized in that the periphery of a rope main
body impregnated with an impregnating solution which contains a
hydroxy compound having two or more hydroxy groups per molecule and
an isocyanate compound having two or more isocyanate groups per
molecule is covered with a molded product of a composition for
forming a covering resin layer, which is produced by mixing a
thermoplastic polyurethane elastomer, a thermoplastic resin other
than the thermoplastic polyurethane elastomer, and an isocyanate
compound having two or more isocyanate groups per molecule. It
should be noted that the impregnating solution has a lower
viscosity than the melt viscosity of the composition for forming a
covering resin layer.
[0040] The elevator rope according to this embodiment is the same
as that in Embodiment 1 except that the rope main body impregnated
with the impregnating solution is used as the rope main body, and
hence descriptions of the covering resin layer are omitted.
Meanwhile, as the rope main body before impregnation with the
impregnating solution, the rope main body as exemplified in
Embodiment 1 may be used. Further, in order to improve adhesion
between the rope main body impregnated with the impregnating
solution and the covering resin layer, an adhesive may be applied
to the rope main body before covering with the covering resin
layer. The type of adhesive is not particularly limited, but
epoxy-based, phenol-based, and urethane-based adhesives are
preferred.
[0041] Examples of the hydroxy compound having two or more hydroxy
groups per molecule, which is used in this embodiment include,
ethylene glycol, propylene glycol, butanediol, diethylene glycol,
3-methylpentane glycol, glycerin, hexanetriol, trimethylolpropane,
and tetraethylene glycol. Those compounds may be used alone or in
combinations of two or more kinds thereof.
[0042] Examples of the isocyanate compound having two or more
isocyanate groups per molecule, which is used in this embodiment,
include: aliphatic isocyanates such as 1,6-hexamethylene
diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, lysine
methyl ester diisocyanate, methylene diisocyanate, isopropylene
diisocyanate, lysine diisocyanate, 1,5-octylene diisocyanate, and a
dimer acid diisocyanate; alicyclic isocyanates such as
4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate,
hydrogenated tolylene diisocyanate, methyl cyclohexane
diisocyanate, and isopropylidene dicyclohexyl-4,4'-diisocyanate;
and aromatic isocyanates such as 2,4- or 2,6-tolylene diisocyanate,
4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate,
xylylene diisocyanate, triphenylmethane triisocyanate,
tris(4-phenyl isocyanate) thiophosphate, tolidine diisocyanate,
p-phenylene diisocyanate, diphenyl ether diisocyanate, and
diphenylsulfone diisocyanate. Those compounds may be used alone or
in combinations of two or more kinds thereof. Alternatively, an
isocyanate prepolymer having isocyanate groups at its molecular
ends, which can be obtained by causing an active hydrogen compound
such as a polyol or a polyamine to react with the above-mentioned
isocyanate, can also be used as the isocyanate compound having two
or more isocyanate groups per molecule.
[0043] The impregnating solution used in this embodiment is
prepared by dissolving the above-mentioned hydroxy compound and
isocyanate compound in a solvent. The solvent used in this case is
not particularly limited as long as the solvent can dissolve the
hydroxy compound and isocyanate compound, and examples thereof
include toluene, methyl isobutyl ketone, methyl ethyl ketone,
xylene, butyl acetate, and ethyl acetate. Those solvents may be
used alone or in combinations of two or more kinds thereof.
Meanwhile, the impregnating solution may be prepared by mixing a
solution obtained by dissolving the hydroxy compound in a solvent
and a solution obtained by dissolving the isocyanate compound in a
solvent. In this case, the solvents used for dissolving the hydroxy
compound and isocyanate compound may have the same composition or
different compositions.
[0044] The ratio between the hydroxy compound and isocyanate
compound in the impregnating solution is not particularly limited,
but is preferably adjusted so as to be hydroxy group:isocyanate
group=1:1.
[0045] FIG. 2 is a schematic cross-sectional view of an example of
an elevator rope obtained by covering the periphery of strands 6
impregnated with no impregnating solution with a covering resin
layer 7 including a molded product of a composition for forming a
covering resin layer, which is produced by mixing a thermoplastic
polyurethane elastomer, a thermoplastic resin other than the
thermoplastic polyurethane elastomer, and an isocyanate compound
having two or more isocyanate groups per molecule. As illustrated
in FIG. 2, in the elevator rope using the strands 6 impregnated
with no impregnating solution, an air layer 8 may appear between
the strands 6 and the covering resin layer 7 due to variations in
production steps (such as a variation in the composition of
materials for forming the covering resin layer, molding
temperature, heat-hardening temperature, and heat-hardening time).
If the air layer 8 appears, it becomes difficult to release heat
generated by friction, e.g., heat generated on a friction interface
at the time of an emergency stop of the elevator, from the friction
interface, and hence the temperature on the friction interface
varies drastically, resulting in a large variation in the friction
coefficient. In many cases, the air layer 8 appears in gaps in the
strands 6 or in valley parts between wires in the strands 6.
[0046] FIG. 3 is a schematic cross-sectional view of an example of
an elevator rope obtained by: impregnating strands 6 with an
impregnating solution which contains a hydroxy compound having two
or more hydroxy groups per molecule and an isocyanate compound
having two or more isocyanate groups per molecule and has a lower
viscosity than the melt viscosity of a composition for forming a
covering resin layer; heating the resultant product at 40.degree.
C. or more and 180.degree. C. or less to mold the product into a
impregnating solution-hardened product 9; and covering the
periphery of the resultant strands 6 with a covering resin layer 7
including a molded product of the composition for forming a
covering resin layer, which is produced by mixing a thermoplastic
polyurethane elastomer, a thermoplastic resin other than the
thermoplastic polyurethane elastomer and an isocyanate compound
having two or more isocyanate groups per molecule.
[0047] As illustrated in FIG. 3, in this embodiment, the rope main
body impregnated with the impregnating solution is heated at
40.degree. C. or more and 180.degree. C. or less to thermally
expand the strands 6, and the impregnating solution penetrates gaps
between wires in the strands 6, the gaps being generated by the
thermal expansion. Further heating is carried out to react and
harden the hydroxy compound having two or more hydroxy groups per
molecule and the isocyanate compound having two or more isocyanate
groups per molecule in the impregnating solution, to thereby fill
the gaps in the strands 6 or the valley parts between wires in the
strands 6 where the air layer 8 is liable to appear with the
impregnating solution-hardened product 9. Subsequently, the rope
main body is covered with the covering resin layer 7 including the
molded product of the composition for forming a covering resin
layer, which is produced by mixing the thermoplastic polyurethane
elastomer, the thermoplastic resin other than the thermoplastic
polyurethane elastomer and the isocyanate compound having two or
more isocyanate groups per molecule, to thereby obtain an elevator
rope without generating the air layer 8. In the thus-obtained
elevator rope, even in the case where frictional heat is suddenly
generated, such as at the time of an emergency stop of the
elevator, heat is easily released, and temperature change on the
friction interface becomes small, resulting in a small variation in
the friction coefficient.
[0048] The viscosity of the impregnating solution before complete
hardening is adjusted so as to be lower than the melt viscosity of
the composition for forming a covering resin layer. In the case
where the viscosity of the impregnating solution before complete
hardening is higher than the melt viscosity of the composition for
forming a covering resin layer, it is impossible to fill gaps in
the strands 6 or valley parts between wires in the strands 6 where
the air layer 8 is liable to appear. The viscosity of the
impregnating solution is appropriately adjusted depending on the
composition of the composition for forming a covering resin layer
and the like, but is usually 500 mPas or more and 20,000 mPas or
less, preferably 2,000 mPas or more and 5,000 mPas or less. The
above-mentioned viscosity ranges are lower than the melt viscosity
of a general thermoplastic polyurethane elastomer, and hence the
impregnating solution can fill small gaps which are not filled by
covering with the covering resin layer 7.
[0049] Meanwhile, in order to improve the thermal conductivity of
the impregnating solution-hardened product 9, a thermally
conductive inorganic filler may be added to the impregnating
solution. The thermally conductive inorganic filler is not
particularly limited, and examples thereof include boron nitride,
aluminum nitride, silicon carbide, silicon nitride, alumina, and
silica. Of those, boron nitride and aluminum nitride are more
preferred because of high thermal conductivity. In addition, the
blending amount of the thermally conductive inorganic filler is not
particularly limited.
[0050] When a rope including steel wires having a multilayer
structure, e.g., a rope having the structure shown in FIG. 1 of WO
2003/050348 A1, is impregnated with the impregnating solution
before covering the outermost periphery with the covering resin
layer and heated at from 40.degree. C. or more to 180.degree. C. or
less, the impregnating solution-hardened product can be filled even
if there are gaps between the steel wires in the rope outermost
layer and the resin cladding where the steel wires in the outermost
layer are twisted. FIG. 4 is a schematic cross-sectional view of
the vicinity of an outer layer of an elevator rope having the
structure shown in FIG. 1 of WO 2003/050348 A1, which is obtained
by forming an impregnating solution-hardened product by the
above-mentioned method before covering with an outer layer
cladding. In FIG. 4, the numeral 9 denotes the impregnating
solution-hardened product, the numeral 10 denotes the outer layer
cladding, the numeral 11 denotes an outer layer strand, and the
numeral 12 denotes an inner layer cladding. The outer layer strands
11 are each structured by a center wire disposed in the center and
six peripheral wires disposed on the periphery of the center wire.
In the elevator rope illustrated in FIG. 4, gaps between wires in
the outer layer strands 11 and gaps between the outer layer strands
11 are filled with the impregnating solution-hardened product 9,
and hence even in the case where frictional heat is suddenly
generated, such as at the time of an emergency stop of the
elevator, heat is easily released, and temperature change on the
friction interface becomes small, resulting in a small variation in
the friction coefficient. Further, even when the rope is bent and
used, damage due to contact between wires can be reduced, and
longer life of the elevator rope can be achieved.
[0051] According to Embodiment 3, it is possible to obtain an
elevator rope having a small variation in the friction coefficient
in a wide range of sliding velocities from a small sliding velocity
range required for maintaining a static condition of an elevator
car to a large sliding velocity range during emergency or sudden
stops of an elevator in operation.
Embodiment 4
[0052] An elevator rope according to Embodiment 4 of the present
invention is characterized in that the periphery of a rope main
body impregnated with an impregnating solution which contains a
hydroxy compound having two or more hydroxy groups per molecule and
an isocyanate compound having two or more isocyanate groups per
molecule is covered with a molded product of a composition for
forming a covering resin layer, which is produced by mixing a
thermoplastic polyurethane elastomer and inorganic fillers. It
should be noted that the impregnating solution has a lower
viscosity than the melt viscosity of the composition for forming a
covering resin layer.
[0053] The elevator rope according to this embodiment is the same
as that in Embodiment 2 except that the rope main body impregnated
with the impregnating solution is used as the rope main body, and
hence descriptions of the covering resin layer are omitted. As the
rope main body before impregnation with the impregnating solution,
the rope main body as exemplified in Embodiment 1 may be used.
Meanwhile, as the impregnating solution, the same impregnating
solution as exemplified in Embodiment 3 may be used, and a method
of forming the impregnating solution-hardened product is the same
as that in Embodiment 3. Therefore, descriptions of them are
omitted. Further, in order to improve adhesion between the rope
main body impregnated with the impregnating solution and the
covering resin layer, an adhesive may be applied to the rope main
body before covering with the covering resin layer. The type of the
adhesive is not particularly limited, but epoxy-based,
phenol-based, and urethane-based adhesives are preferred.
[0054] In this embodiment, the rope main body impregnated with the
impregnating solution is heated at 40.degree. C. or more and
180.degree. C. or less to thermally expand the strand, and the
impregnating solution penetrates gaps between wires in the strand,
the gaps being generated by the thermal expansion. Further, heating
is carried out to react and harden the hydroxy compound having two
or more hydroxy groups per molecule and the isocyanate compound
having two or more isocyanate groups per molecule in the
impregnating solution, to thereby fill the gaps in the strand or
the valley parts between wires in the strand where an air layer is
liable to appear with the impregnating solution-hardened product.
Subsequently, the rope main body is covered with the covering resin
layer including the molded product of the composition for forming a
covering resin layer, which is produced by mixing the thermoplastic
polyurethane elastomer and the inorganic filler, to thereby obtain
the elevator rope without generating the air layer. In the
thus-obtained elevator rope, even in the case where frictional heat
is suddenly generated, such as at the time of an emergency stop of
the elevator, heat is easily released, and temperature change on
the friction interface becomes small, resulting in a small
variation in the friction coefficient.
[0055] According to Embodiment 4, it is possible to obtain an
elevator rope having a small variation in the friction coefficient
in a wide range of sliding velocities from a small sliding velocity
range required for maintaining a static condition of an elevator
car to a large sliding velocity range during emergency or sudden
stops of an elevator in operation.
EXAMPLES
[0056] Hereinafter, the present invention is described in more
detail by way of examples and comparative examples, but is not
limited by the examples.
Example 1
[0057] 5 parts by mass of an isocyanate batch obtained by kneading
1.85 parts by mass of a polystyrene resin, 1.3 parts by mass of an
epoxy resin, and 1.85 parts by mass of 4,4'-diphenylmethane
diisocyanate using a twin screw extruder were added to 100 parts by
mass of an ether-based thermoplastic polyurethane elastomer having
a JIS A hardness of 85, and the resultant was mixed well and
supplied to an extrusion molding machine, to thereby mold the
mixture as a covering resin layer for covering the periphery of a
rope main body. The rope main body was covered with the covering
resin layer and then heated at 100.degree. C. for 2 hours to
promote a reaction between the ether-based thermoplastic
polyurethane elastomer and the isocyanate batch, to thereby obtain
an elevator rope having a diameter of 12 mm. It should be noted
that the resultant elevator rope had the cross-sectional structure
described in FIG. 1 of WO 2003/050348 A1. Here, the rope main body
corresponds to the elevator rope including: the inner layer rope
having a plurality of core strands in each of which a plurality of
steel wires are twisted together and a plurality of inner layer
strands in each of which a plurality of steel wires are twisted
together; the inner layer cladding made of a resin and covering the
periphery of the inner layer rope; and the outer layer rope
provided in a peripheral portion of the inner layer cladding and
having a plurality of outer layer strands in each of which a
plurality of steel wires are twisted together, and the covering
resin layer corresponds to the outer layer cladding. Before
covering the rope main body with the covering resin layer, Chemlok
(registered trademark) 218 (manufactured by LORD Far East, Inc.)
was applied to the peripheral strands of the rope main body and
dried.
Example 2
[0058] The same procedure as in Example 1 was carried out except
that the amount of the isocyanate batch added was changed to 20
parts by mass, to thereby obtain an elevator rope.
Example 3
[0059] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 90 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
to thereby obtain an elevator rope.
Example 4
[0060] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 90 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and the amount of the isocyanate batch added was changed to 15
parts by mass, to thereby obtain an elevator rope.
Example 5
[0061] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 95 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
to thereby obtain an elevator rope.
Example 6
[0062] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 95 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and the amount of the isocyanate batch added was changed to 10
parts by mass, to thereby obtain an elevator rope.
Example 7
[0063] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 95 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and 10 parts by mass of calcium carbonate were used instead of the
isocyanate batch, to thereby obtain an elevator rope.
Example 8
[0064] The same procedure as in Example 7 was carried out except
that 5 parts by mass of carbon black were used instead of 10 parts
by mass of calcium carbonate, to thereby obtain an elevator
rope.
Example 9
[0065] The same procedure as in Example 7 was carried out except
that 10 parts by mass of talc were used instead of 10 parts by mass
of calcium carbonate, to thereby obtain an elevator rope.
Example 10
[0066] The same procedure as in Example 7 was carried out except
that 10 parts by mass of titanium oxide were used instead of 10
parts by mass of calcium carbonate, to thereby obtain an elevator
rope.
Example 11
[0067] The same procedure as in Example 7 was carried out except
that 10 parts by mass of silica were used instead of 10 parts by
mass of calcium carbonate, to thereby obtain an elevator rope.
Example 12
[0068] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 90 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and 10 parts by mass of a glass fiber were used instead of the
isocyanate batch, to thereby obtain an elevator rope.
Example 13
[0069] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 95 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and 10 parts by mass of calcium carbonate and 10 parts by mass of
the isocyanate batch were used instead of 5 parts by mass of the
isocyanate batch, to thereby obtain an elevator rope.
Example 14
[0070] The same procedure as in Example 13 was carried out except
that 5 parts by mass of carbon black were used instead of 10 parts
by mass of calcium carbonate, to thereby obtain an elevator
rope.
Example 15
[0071] The same procedure as in Example 13 was carried out except
that 10 parts by mass of talc were used instead of 10 parts by mass
of calcium carbonate, to thereby obtain an elevator rope.
Example 16
[0072] The same procedure as in Example 13 was carried out except
that 10 parts by mass of titanium oxide were used instead of 10
parts by mass of calcium carbonate, to thereby obtain an elevator
rope.
Example 17
[0073] The same procedure as in Example 13 was carried out except
that 10 parts by mass of silica were used instead of 10 parts by
mass of calcium carbonate, to thereby obtain an elevator rope.
Example 18
[0074] The same procedure as in Example 13 was carried out except
that 10 parts by mass of mica were used instead of 10 parts by mass
of calcium carbonate, to thereby obtain an elevator rope.
Example 19
[0075] The same procedure as in Example 1 was carried out except
that an ether-based thermoplastic polyurethane elastomer having a
JIS A hardness of 90 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
and 10 parts by mass of a glass fiber and 10 parts by mass of the
isocyanate batch were used instead of 5 parts by mass of the
isocyanate batch, to thereby obtain an elevator rope.
Example 20
[0076] The same procedure as in Example 19 was carried out except
that 10 parts by mass of a carbon fiber were used instead of 10
parts by mass of the glass fiber, to thereby obtain an elevator
rope.
Example 21
[0077] The same rope main body as in Example 1 was impregnated with
an impregnating solution (viscosity 2,500 mPas) obtained by mixing
a solution prepared by dissolving ethylene glycol in methyl ethyl
ketone and a solution prepared by dissolving 4,4'-diphenylmethane
diisocyanate in butyl acetate, and heated at 120.degree. C., to
thereby obtain a rope main body subjected to the impregnating
treatment. Subsequently, 5 parts by mass of an isocyanate batch
obtained by kneading 1.85 parts by mass of a polystyrene resin, 1.3
parts by mass of an epoxy resin, and 1.85 parts by mass of
4,4'-diphenylmethane diisocyanate using a twin screw extruder were
added to 100 parts by mass of an ether-based thermoplastic
polyurethane elastomer having a JIS A hardness of 95, and the
resultant was mixed well and supplied to an extrusion molding
machine, to thereby mold the mixture as a covering resin layer for
covering the periphery of the rope main body obtained above. It
should be noted that the melt viscosity of the composition for
forming a covering resin layer was 1.0.times.10.sup.7 mPas. The
rope main body was covered with the covering resin layer and then
heated at 100.degree. C. for 2 hours to promote a reaction between
the ether-based thermoplastic polyurethane elastomer and the
isocyanate batch, to thereby obtain an elevator rope having a
diameter of 12 mm. It should be noted that before covering the rope
main body with the covering resin layer, Chemlok (registered
trademark) 218 (manufactured by LORD Far East, Inc.) was applied to
the peripheral strands of the rope main body and dried.
Example 22
[0078] The same procedure as in Example 21 was carried out except
that 10 parts by mass of talc were used instead of 5 parts by mass
of the isocyanate batch, to thereby obtain an elevator rope. It
should be noted that the melt viscosity of the composition for
forming a covering resin layer was 1.0.times.10.sup.7 mPas.
Example 23
[0079] The same procedure as in Example 21 was carried out except
that 10 parts by mass of talc were used instead of 5 parts by mass
of the isocyanate batch, to thereby obtain an elevator rope. It
should be noted that the melt viscosity of the composition for
forming a covering resin layer was 1.0.times.10.sup.7 mPas.
Comparative Example 1
[0080] The same procedure as in Example 1 was carried out except
that only the ether-based thermoplastic polyurethane elastomer
having a JIS A hardness of 85 was used without using the isocyanate
batch, to thereby obtain an elevator rope.
Comparative Example 2
[0081] The same procedure as in Comparative Example 1 was carried
out except that an ether-based thermoplastic polyurethane elastomer
having a JIS A hardness of 90 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
to thereby obtain an elevator rope.
Comparative Example 3
[0082] The same procedure as in Comparative Example 1 was carried
out except that an ether-based thermoplastic polyurethane elastomer
having a JIS A hardness of 95 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
to thereby obtain an elevator rope.
Comparative Example 4
[0083] The same procedure as in Comparative Example 1 was carried
out except that an ether-based thermoplastic polyurethane elastomer
having a JIS A hardness of 98 was used instead of the ether-based
thermoplastic polyurethane elastomer having a JIS A hardness of 85,
to thereby obtain an elevator rope.
[Measurement of Glass Transition Temperature (Tg) of Covering Resin
Layer]
[0084] The glass transition temperature (Tg) of the covering resin
layer was measured as follows. A composition for molding having the
same composition as that of the covering resin layer used in each
of the Examples and Comparative Examples was supplied to an
extrusion molding machine and molded into a plate having a size of
100 mm.times.100 mm.times.thickness 2 mm, followed by heating at
100.degree. C. for 2 hours, and then a test piece having a size of
50 mm.times.10 mm.times.thickness 2 mm was cut off from the center
portion of the plate. The loss modulus of the test piece was
measured using a viscoelastic spectrometer DMS120 manufactured by
Seiko Instruments Inc. under conditions of deformation mode:
bending mode, measurement frequency: 10 Hz, temperature increase
rate: 2.degree. C./min, and vibration amplitude: 10 .mu.m, and the
peak temperature of the loss modulus was adopted as Tg. Table 1
shows the results.
[JIS A Hardness of Covering Resin Layer]
[0085] According to JIS K7215, a type A durometer was used to
measure durometer A hardness. Table 1 shows the results.
[Measurement of Friction Coefficient of Rope]
[0086] (1) Measurement Method in Small Sliding Velocity Range
[0087] FIG. 5 is a conceptual diagram of an apparatus for measuring
the friction coefficient in a small sliding velocity range. As
illustrated in FIG. 5, an elevator rope 1 obtained in each of the
Examples and Comparative Examples was twisted 180 degrees around a
sheave 2, and one end thereof was fixed on a measurement apparatus
3. The other end was connected to a weight 4, and a tension was
applied to the elevator rope 1. Here, when the sheave 2 was rotated
in a clockwise direction at a predetermined rate, rope tension on
the fixed side (T.sub.2) loosens just for the friction force
between the elevator rope 1 and the sheave 2, resulting in a
tension difference from rope tension on the weight side (T.sub.2).
The rope tension on the weight side (T.sub.1) and rope tension on
the fixed side (T.sub.2) were measured using a load cell provided
on the connection part between the rope and the weight. The small
sliding velocity range was defined as 1.times.10.sup.-5 mm/s or
less, and T.sub.1 and T.sub.2 (provided that T.sub.1>T.sub.2), a
contact angle of the rope on the sheave .theta. (=180 degrees), and
a coefficient K.sub.2 (=1.19) determined by the shape of the groove
of the sheave were substituted into the following equation 1, to
thereby determine a friction coefficient .mu..sub.i between the
elevator rope 1 and the sheave 2. Table 1 shows the results.
.mu. 1 = ln ( T 1 / T 2 ) K 2 .theta. ( Equation 1 )
##EQU00001##
[0088] (2) Measurement Method in Large Sliding Velocity Range at
the Time of an Emergency Stop
[0089] FIG. 6 is a conceptual diagram of an apparatus for measuring
a friction coefficient in a large sliding velocity range at the
time of an emergency stop. The elevator rope 1 obtained in each of
the Examples and Comparative Examples was twisted 180 degrees
around a driving sheave 5. One end thereof was connected to a
weight 4a, and the other end was connected to a weight 4b having a
larger mass than the weight 4a. The rope groove of the driving
sheave 5 used here was a U-shaped groove having a size of .PHI.15
mm and depth 20 mm, and no further special processing was performed
on the sheave. The driving sheave 5 was rotated in a clockwise
direction to raise the weight 4a, and the driving sheave 5 was
suddenly stopped when the rope speed reached 4 m/s, to thereby have
the elevator rope 1 slip against the driving sheave 5. In this
case, the minimum deceleration .alpha. of the weight 4a, the
tension on the weight 4a side (T.sub.3), and the tension on the
weight 4b side (T.sub.4) were measured using a load cell provided
on the connection part between the rope and the weight, and the
resultant values were substituted into the following equation 2, to
thereby determine a minimum friction coefficient .mu..sub.2 during
slipping. Table 1 shows the results.
.mu. 2 = ln ( T 4 ( 1 + .alpha. / g ) / T 3 ( 1 + .alpha. / g ) ) K
2 .theta. ( Equation 2 ) ##EQU00002##
[0090] Here, K.sub.2 represents the same value as that used in the
measurement method in the small sliding velocity range, g
represents a gravity constant (=9.80665 m/s.sup.2), and .theta.
represents a contact angle of the rope on the sheave (=180
degrees).
[0091] It should be noted that a rope having a rope friction
coefficient of less than 0.15 was estimated as x, a rope having a
rope friction coefficient of 0.15 or more and less than 0.2 was
estimated as .DELTA., a rope having a rope friction coefficient of
0.2 or more and less than 0.25 was estimated as o, and a rope
having a rope friction coefficient of 0.25 or more was estimated as
.circleincircle..
TABLE-US-00001 TABLE 1 Glass transition temperature JIS A Friction
coefficient (.degree. C.) hardness Small sliding Emergency stop
Example 1 -42 86 .DELTA. .DELTA. Example 2 -38 88 .DELTA. .DELTA.
Example 3 -39 91 .DELTA. .DELTA. Example 4 -36 94 .DELTA. .DELTA.
Example 5 -29 96 .largecircle. .DELTA. Example 6 -28 97
.largecircle. .DELTA. Example 7 -27 95 .largecircle. .DELTA.
Example 8 -26 95 .largecircle. .DELTA. Example 9 -25 96
.largecircle. .DELTA. Example 10 -25 95 .largecircle. .DELTA.
Example 11 -22 95 .largecircle. .DELTA. Example 12 -24 94
.largecircle. .DELTA. Example 13 -25 97 .largecircle. .largecircle.
Example 14 -25 96 .largecircle. .largecircle. Example 15 -25 97
.largecircle. .circleincircle. Example 16 -24 97 .largecircle.
.largecircle. Example 17 -21 98 .largecircle. .circleincircle.
Example 18 -23 98 .largecircle. .largecircle. Example 19 -25 97
.largecircle. .circleincircle. Example 20 -22 97 .largecircle.
.circleincircle. Example 21 -43 88 .largecircle. .largecircle.
Example 22 -25 93 .largecircle. .circleincircle. Example 23 -26 95
.largecircle. .circleincircle. Comparative -43 85 X X Example 1
Comparative -40 90 X X Example 2 Comparative -30 95 X X Example 3
Comparative -10 98 .DELTA. X Example 4
[0092] As is clear from the results shown in Table 1, the friction
coefficients in the small sliding velocity range (1.times.10.sup.-5
mm/s) and at the time of an emergency stop, determined using the
elevator ropes obtained in the Examples and Comparative Examples,
were found to have a tendency of being lower than the friction
coefficients during normal operation (0.3 to 0.4). All the elevator
ropes obtained in the Examples were found to have friction
coefficients of 0.15 or more in the small sliding velocity range
and at the time of an emergency stop, and about 40% of the friction
coefficient was able to be maintained compared with the friction
coefficient during normal operation. In particular, in Examples 13
to 20 where the isocyanate compound serving as a cross-linking
agent and the inorganic filler were used in combination, variations
in the friction coefficients were found to be small. Specifically,
in the cases of the ropes having added thereto the plate-like
inorganic filler such as talc or mica and the ropes having added
thereto the fibrous inorganic filler such as the glass fiber or the
carbon fiber, variations in the friction coefficients were found to
be small. Meanwhile, in the cases of the elevator ropes of Examples
21 to 23, variations in the friction coefficients at the time of an
emergency stop were found to be smaller than those of the ropes
impregnated with no impregnating solution (Examples 5, 9, and
15).
[0093] On the other hand, in the cases of all the elevator ropes
obtained in the Comparative Examples, variations in the friction
coefficients were large, and the friction coefficients were less
than 0.15.
REFERENCE SIGNS LIST
[0094] 1 elevator rope, 2 sheave, 3 measurement apparatus, 4, 4a,
4b weight, 5 driving sheave, 6 strand, 7 covering resin layer, 8
air layer, 9 impregnating solution-hardened product, 10 outer layer
cladding, 11 outer layer strand, 12 inner layer cladding.
* * * * *